1. Field of the Invention
The present invention relates to circuit board connections to the computer frame, for power, for cooling and to other boards.
2. DESCRIPTION OF THE PRIOR ART
High speed supercomputers of the type produced by Cray Research, Inc., the assignee hereof, utilize stacks of interconnected circuit modules. Each circuit module typically includes a pair of printed circuit boards mounted on opposite sides of a heat sink, commonly referred to as a cold plate, or a pair of cold plates sandwiched by two or more boards. Each circuit board in turn includes numerous integrated and discrete circuit, logic, and memory devices. The cold plates have liquid coolant filled channels winding back and forth to carry heat away. The stacks of boards require large electrical power and ground connections as well as circuit connections. In addition, the stacks have liquid coolant pumped throughout the cold plates and need liquid coolant inputs and outputs.
The power and ground connections should have as large an area as is reasonably possible. The electrical resistance decreases as the cross sectional area through which the current flows increases. Therefore, it is advantageous to provide connections having a very large area of contact to optimize performance.
It is also necessary to provide both an input and an output for liquid coolant. The coolant is pumped through channels winding back and forth in the cold plate between pairs of boards in a module and through a heat exchanger before returning to the module.
Considerable time must also be spent connecting and disconnecting the connections for input and output signals to the circuit boards. Hundreds of connections must be made and proper alignment and connection of each electrical connector is critical.
Should problems develop with a board and repair or replacement be required, the module must be removed so that the repair work may be conducted. The supercomputer down time is quite costly so that it is important to have the repairs completed as quickly as possible. Removing and replacing a board has heretofore taken on the order of at least 30 minutes. A substantial portion of that time is spent bolting and unbolting the connections between the board and the frame. In addition, since the channels between the boards are substantially horizontal and are filled with coolant, great care must be taken so that no spilling occurs which may damage computer components. A quicker connect and disconnect would save a substantial amount of time and greatly reduce repair costs due to computer downtime. Automatic connection and disconnection and alignment would increase reliability and minimize repair time.
It can be seen then, that a circuit board module is needed which connects to a computer frame that provides for quick and reliable connection and disconnection of the several types of inputs and outputs of circuit boards to decrease module repair and replacement time. Quick and reliable connections are needed for liquid coolant, electrical power, electrical ground, and input and output signals from the module. The present invention addresses these and other problems associated with computer circuit board modules.